Field
The present disclosure relates to network management. More specifically, the present disclosure relates to a method and system for monitoring the health of a virtual extensible local area network (LAN), or VXLAN, tunnel based on a keepalive mechanism.
Related Art
The exponential growth of the Internet has made it a popular delivery medium for multimedia applications, such as video on demand and television. Such applications have brought with them an increasing demand for bandwidth. As a result, equipment vendors race to build larger and faster switches with versatile capabilities, such as service insertion and provisioning, to move more traffic efficiently. However, the size of a switch cannot grow infinitely. It is limited by physical space, power consumption, and design complexity, to name a few factors. Furthermore, switches with higher capability are usually more complex and expensive. More importantly, because an overly large and complex system often does not provide economy of scale, simply increasing the size and capability of a switch may prove economically unviable due to the increased per-port cost.
A flexible way to improve the scalability of a switch system is to build a fabric switch. A fabric switch is a collection of individual member switches. These member switches form a single, logical switch that can have an arbitrary number of ports and an arbitrary topology. As demands grow, customers can adopt a “pay as you grow” approach to scale up the capacity of the fabric switch.
Meanwhile, layer-2 (e.g., Ethernet) switching technologies continue to evolve. More routing-like functionalities, which have traditionally been the characteristics of layer-3 (e.g., Internet Protocol or IP) networks, are migrating into layer-2. Notably, the recent development of the Transparent Interconnection of Lots of Links (TRILL) protocol allows Ethernet switches to function more like routing devices. TRILL overcomes the inherent inefficiency of the conventional spanning tree protocol, which forces layer-2 switches to be coupled in a logical spanning-tree topology to avoid looping. TRILL allows routing bridges (RBridges) to be coupled in an arbitrary topology without the risk of looping by implementing routing functions in switches and including a hop count in the TRILL header.
As Internet traffic is becoming more diverse, virtual computing in a network is becoming progressively more important as a value proposition for network architects. For example, virtual extensible local area network (VXLAN) is a network virtualization technology which facilitates an overlay encapsulation protocol, e.g., by providing a layer-3 encapsulation of a layer-2 frame through a VXLAN tunnel. However, because VXLAN tunnels are stateless, a source VXLAN tunnel endpoint (VTEP) typically does not maintain information related to the availability of a destination VTEP. If the destination VTEP is unreachable, the source VTEP may remain unaware and may not be able to bring the tunnel down. This can result in inefficient path utilization. Thus, while overlay tunneling brings many desirable features to a network, some issues remain unsolved in monitoring the health of a VXLAN tunnel.